604 AUSCULTATION. 



responds to the abdominal cavity. It follows that the last 

 intercostal space, the lower two-thirds of the twelfth rib, and 

 all that part behind a line drawn from this point to the 

 posterior bone of the sternum, responds to the abdominal 

 cavity and not to the thorax. 



Sheep. In this species the thorax may be examined in 

 fche same way as in the ox, this difference only being borne 

 in mind, that the diaphragm, like that of the horse, is inserted 

 on the false ribs close to their cartilages, so that the latter, 

 and the extreme ends of some of the posterior ribs alone, 

 belong to the abdominal cavity. 



Pig. In this subject, the thorax can only be explored 

 behind the shoulders, which are thick and possessed of little 

 mobility. The diaphragm is attached to the upper two-thirds 

 of the last rib, and to the three ribs next in front, imme- 

 diately above their lower third, so that all above and in front 

 of this responds to the thoracic viscera. 



Dog and Gat. The thorax of these animals is nearly all 

 open for examination. The shoulders are thin and extremely 

 mobile, and the rest of the chest is covered only by a thin 

 layer of muscle. The diaphragm is attached to the lower 

 end of all the false ribs except the two last, the lower third 

 of which may be said to be extra-thoracic. 



Birds. The anterior aspect of the bird's thorax is covered 

 by enormous pectoral muscles which prevent all exploration 

 of this part. This is less necessary, however, from the lungs 

 of these animals being lodged in the posterior part of this 

 cavity, which is very open to observation from the thinness, 

 or almost complete absence of muscles on the back and under 

 the wings. 



The larger quadrupeds may be examined standing in their 

 ordinary position ; but such a practice is attended with con- 

 siderable disadvantage in the case of the smaller subjects. 



